This doesn't sound like a hard problem to solve. Give everyone a basic personal amount for free and charge for anything above that.
Though basic individual usage is really not the problem, anyways. Households don't use all that much water, and most of it can be returned to the waterways after treatment. Water pricing is much more important for affecting the behaviour of businesses.
Though basic individual usage is really not the problem, anyways. Households don't use all that much water, and most of it can be returned to the waterways after treatment. Water pricing is much more important for affecting the behaviour of businesses.